Healthy sleep patterns, alertness on waking up may be affected by tablet devices

Regular use of phones and computers at night delays the sleep timings of people, a study has found.

Using cell phones late at night can lead to less alertness on waking up in the morning. (Shutterstock)

Using light-emitting tablet devices in the evenings can lead to extended bedtimes, play havoc with a sleep-regulating hormone and affect the level of alertness in the morning, according to a recent study.

The study, which was published in the journal Physiological Reports, studied nine healthy adults for five consecutive evenings of unhindered use of light-emitting tablet computers compared to evenings when they simply read books, magazines or newspapers.

“These findings provide more evidence that light-emitting electronic devices have biological effects,” said Jeanne Duffy, from Harvard Medical School in the US.

“Using light-emitting electronic devices in the late evening can postpone our decision to go to sleep, and make us more sleepy the next morning,” said Duffy.

When they used light-emitting tablets, participants’ bedtimes were delayed by half an hour on average, their melatonin levels were suppressed, the timing of melatonin secretion was delayed and so was the onset of sleep. Melatonin is the hormone which helps in regulating sleep.

Another study had found that due to the blue light emitted by smartphone screens, children and teenagers specifically had disrupted sleep, showing that younger people are face more of the negative affects of these devices.

According to researchers this was because brains, sleep patterns, and eyes were still developing in children and teenagers. “We know younger individuals have larger pupils, and their lenses are more transparent, so their exposure and sensitivity to that light is even greater than in older individuals,” said Monique LeBourgeois, associate professor at the University of Colorado Boulder in the US.